hw/arm/virt: tcg: adjust MPIDR like KVM

KVM adjusts the MPIDR of guest vcpus based on the architecture of
the host, 32-bit vs. 64-bit, and, for 64-bit, also on the type of
GIC the guest is using. To be consistent and improve SGI efficiency
we make the same adjustments for TCG as 64-bit KVM hosts. We neglect
to add consistency with 32-bit KVM hosts, as that would reduce SGI
efficiency and KVM is expected to change.

As MPIDR is a system register, and thus guest visible, we only make
adjustments for current and later versioned machines.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Message-id: 1467378129-23302-3-git-send-email-drjones@redhat.com
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/arm/virt.c

@@ -52,7 +52,8 @@
 #include "hw/arm/sysbus-fdt.h"
 #include "hw/platform-bus.h"
 #include "hw/arm/fdt.h"
-#include "hw/intc/arm_gic_common.h"
+#include "hw/intc/arm_gic.h"
+#include "hw/intc/arm_gicv3_common.h"
 #include "kvm_arm.h"
 #include "hw/smbios/smbios.h"
 #include "qapi/visitor.h"
@@ -82,6 +83,7 @@ typedef struct VirtBoardInfo {
 typedef struct {
     MachineClass parent;
     VirtBoardInfo *daughterboard;
+    bool disallow_affinity_adjustment;
 } VirtMachineClass;
 
 typedef struct {
@@ -1165,6 +1167,7 @@ void virt_guest_info_machine_done(Notifier *notifier, void *data)
 static void machvirt_init(MachineState *machine)
 {
     VirtMachineState *vms = VIRT_MACHINE(machine);
+    VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(machine);
     qemu_irq pic[NUM_IRQS];
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *secure_sysmem = NULL;
@@ -1181,6 +1184,7 @@ static void machvirt_init(MachineState *machine)
     CPUClass *cc;
     Error *err = NULL;
     bool firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
+    uint8_t clustersz;
 
     if (!cpu_model) {
         cpu_model = "cortex-a15";
@@ -1226,8 +1230,10 @@ static void machvirt_init(MachineState *machine)
      */
     if (gic_version == 3) {
         virt_max_cpus = vbi->memmap[VIRT_GIC_REDIST].size / 0x20000;
+        clustersz = GICV3_TARGETLIST_BITS;
     } else {
         virt_max_cpus = GIC_NCPU;
+        clustersz = GIC_TARGETLIST_BITS;
     }
 
     if (max_cpus > virt_max_cpus) {
@@ -1281,6 +1287,20 @@ static void machvirt_init(MachineState *machine)
 
     for (n = 0; n < smp_cpus; n++) {
         Object *cpuobj = object_new(typename);
+        if (!vmc->disallow_affinity_adjustment) {
+            /* Adjust MPIDR like 64-bit KVM hosts, which incorporate the
+             * GIC's target-list limitations. 32-bit KVM hosts currently
+             * always create clusters of 4 CPUs, but that is expected to
+             * change when they gain support for gicv3. When KVM is enabled
+             * it will override the changes we make here, therefore our
+             * purposes are to make TCG consistent (with 64-bit KVM hosts)
+             * and to improve SGI efficiency.
+             */
+            uint8_t aff1 = n / clustersz;
+            uint8_t aff0 = n % clustersz;
+            object_property_set_int(cpuobj, (aff1 << ARM_AFF1_SHIFT) | aff0,
+                                    "mp-affinity", NULL);
+        }
 
         if (!vms->secure) {
             object_property_set_bool(cpuobj, false, "has_el3", NULL);
@@ -1507,7 +1527,10 @@ static void virt_2_6_instance_init(Object *obj)
 
 static void virt_machine_2_6_options(MachineClass *mc)
 {
+    VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
+
     virt_machine_2_7_options(mc);
     SET_MACHINE_COMPAT(mc, VIRT_COMPAT_2_6);
+    vmc->disallow_affinity_adjustment = true;
 }
 DEFINE_VIRT_MACHINE(2, 6)